1. Field of the Invention
The present invention relates to a composition of matter useful as a pigment grinding vehicle and to pigment pastes formulated with such pigment grinding vehicles.
2. Brief Description of the Prior Art
In the formation of paints and especially electrodepositable paints, an important factor is the introduction of pigments into the paint. Pigments are typically ground with a grinding vehicle to form a pigment paste. The resultant paste is then combined with the film forming resin and optional ingredients to form the paint, giving the paint the proper color, or opacity, and application or film properties.
A problem with many pastes used for electrodeposition is the relatively low ratio of pigment to grinding vehicle which can be used. In cationic electrodepositable paints, pigment to grinding vehicle weight ratios are typically 5 to 1 or less. Pastes with higher ratios are not stable. Also, many pigment grinding vehicles do not contribute to, and may actually detract from some of the desirable properties of the resultant coating, particularly the property of corrosion resistance.
The present invention provides for pigment grinding vehicles which can be used to formulate a stable pigment paste having a relatively high pigment to grinding vehicle weight ratio. Also the instant pigment grinding vehicles enhance the corrosion resistance of the resultant coating.